The goal of this research is to develop a nasal spray which could be used to make mammograms easier to read by reducing breast density which may allow earlier recognition of any abnormality of the breast tissue. There is evidence that breast density decreases when exposure to steroid hormones is decreased. Some examples of this are a decrease in breast density at menopause, when ovaries are removed, or when a drug is taken that reduces hormone production. Whether these effects occur in women at high risk of breast cancer is not known. The ovary normally produces the hormone progesterone as well as estrogen and testosterone. The drug deslorelin is known to suppress the production of these hormones by the ovary. The purpose of this study is to demonstrate that deslorelin will decrease breast density thereby making it easier to interpret mammograms and that deslorelin can be combined with estrogen (estrodial) and testosterone in a nasal spray at doses that are sufficient to maintain a woman in good health and still achieve decreased breast density. We hypothesize that the regimen will result in a reduction in mammographic densities as well as a reduction in breast cell proliferation. If these hypotheses are true, the regimen would not only result in enhanced mammographic screening (and facilitate detection of asymptotic cancers), but could potentially be associated with a reduced risk of breast cancer. Given that many women at highest risk for breast cancer consider prophylactic bilateral mastectomy and an option to decrease breast cancer risk, we feel that the potential risk/benefit ration for this protocol is well justified. Moreover, with the recent closure of the NSABP_P1 Breast Cancer Prevention Trial ('tamoxifen trial'), there are currently no available prevention trials for these women. Moreover, the follow-up NSABP trial (P2), comparing tamoxifen and relaxofene, will be restricted to post-menopausal women. Eligible subjects are pre-menopausal women with an increased risk of breast cancer on the basis of a germline BCRA1 mutation or other specified clinical risk criteria based on family history. The participation of an individual subject is expected to last approximately 14 months.